Clearing an array

[Terry Andersen]

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more? Without running
a whole for loop?

Best Regards
Terry

[Robert Stankowic]

"Terry Andersen" <te**@sea.com > schrieb im Newsbeitrag
news:bk******** **@news.net.uni-c.dk...

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more? Without running a whole for loop?

memset(Buffer, 0x00, sizeof Buffer);

Robert

[pete]

Terry Andersen wrote:

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more?
Without running a whole for loop?

A loop might be best.
There's no single operation that will do it.

[pete]

Robert Stankowic wrote:

"Terry Andersen" <te**@sea.com > schrieb im Newsbeitrag
news:bk******** **@news.net.uni-c.dk...

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more?

Without running a whole for loop?

memset(Buffer, 0x00, sizeof Buffer);

Not knowing the representation of ((*Buffer)0),
memset() might or might not work right.

[Lew Pitcher]

On Mon, 15 Sep 2003 15:26:35 +0200, "Terry Andersen" <te**@sea.com > wrote:

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more? Without running
a whole for loop?
#include <string.h>

memset(Buffer, 0, sizeof Buffer);
Best Regards
Terry

--
Lew Pitcher
IT Consultant, Enterprise Technology Solutions
Toronto Dominion Bank Financial Group

(Opinions expressed are my own, not my employers')

[Ed Morton]

Terry Andersen wrote:

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more? Without running
a whole for loop?

Best Regards
Terry

If you can put it inside a structure, you could create a zero-filled
instance and assign your buffer to that, e.g. this:

#include<stdio. h>
#include<string .h>

#define BUFFSIZE 9

typedef struct {
int Buffer[BUFFSIZE];
} BUFFSTRUCT;

static const BUFFSTRUCT ZeroBuffStruct;

void prtBuf(int buf[])
{
int i;
for (i=0; i<BUFFSIZE; i++)
printf("%d",buf[i]);
printf("\n");
}

int main()
{
BUFFSTRUCT BufStruct;
int *Buffer = BufStruct.Buffe r;

BufStruct = ZeroBuffStruct;
prtBuf(Buffer);

Buffer[3] = 4;
prtBuf(Buffer);

BufStruct = ZeroBuffStruct;
prtBuf(Buffer);

return 1;
}

produces the output:

Buffer="0000000 0"
Buffer="0004000 0"
Buffer="0000000 0"

If that's non-portable or has other problems, I'm sure someone will let
us know....

Regards,

Ed.

[Thomas Pfaff]

Le*********@td. com (Lew Pitcher) writes:

On Mon, 15 Sep 2003 15:26:35 +0200, "Terry Andersen" <te**@sea.com > wrote:

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more? Without running
a whole for loop?

#include <string.h>

memset(Buffer, 0, sizeof Buffer);

That's not guaranteed to work unless `Buffer' is of type unsigned char, is it?

[Robert Stankowic]

"pete" <pf*****@mindsp ring.com> schrieb im Newsbeitrag
news:3F******** **@mindspring.c om...

Robert Stankowic wrote:

"Terry Andersen" <te**@sea.com > schrieb im Newsbeitrag
news:bk******** **@news.net.uni-c.dk...

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more?

Without running a whole for loop?

memset(Buffer, 0x00, sizeof Buffer);

Not knowing the representation of ((*Buffer)0),
memset() might or might not work right.

You are ritght, of course. Somehow the 0x00 made me think of unsigned char.
Shame on me.
Robert

[Thomas Matthews]

Thomas Pfaff wrote:

Le*********@td. com (Lew Pitcher) writes:

On Mon, 15 Sep 2003 15:26:35 +0200, "Terry Andersen" <te**@sea.com > wrote:

I have an array that I initialize to zero, like:

Buffer[300] = {0x00};

How do I in my code reset this array to all zeros ones more? Without running
a whole for loop?

#include <string.h>

memset(Buffer, 0, sizeof Buffer);

That's not guaranteed to work unless `Buffer' is of type unsigned char, is it?

It will work on any platform where the data type of buffer can be set
to zero in all bytes. If the platform has a data type where the value
of zero is not zeros in all bytes, then it won't work.

--
Thomas Matthews

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Other sites:
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[Christopher Benson-Manica]

pete <pf*****@mindsp ring.com> spoke thus:

Not knowing the representation of ((*Buffer)0),
memset() might or might not work right.

Why is this so? Are you saying that if Buffer were

long Buffer[300];

that memset wouldn't work, even if you did

memset( Buffer, 0, 300 * sizeof(long) );

?

--
Christopher Benson-Manica | Jumonji giri, for honour.
ataru(at)cybers pace.org |